Đáp án + Giải thích các bước giải:
`a,` Để `A` là phân số thì :
`2n-4\ne0->2n\ne4->n\ne2`
`b,` Để `A` là số nguyên thì :
`2n+2` $\vdots$ `2n-4`
Ta có : `2n+2=(2n-4)+6`
Vì `(2n-4)` $\vdots$ `2n-4`
Nên để `2n+2` $\vdots$ `2n-4`
Thì `6` $\vdots$ `2n-4`
`→2n-4∈Ư(6)`
`→2n-4∈{±1;±2;±3;±6}`
`→2n∈{3;2;1;-2;5;6;7;10}`
`→n∈{\frac{3}{2};1;\frac{1}{2};-1;\frac{5}{2};3;\frac{7}{2};5}`
Mà `n∈Z`
`→n∈{1;-1;3;5}` ( Thỏa Mãn )
Vậy để `A∈Z` thì `n∈{1;-1;3;5}`
`a)`
Để ` A` là phân số `\to 2n -4 \ne 0=> 2n \ne 4 => n \ne2`
`b)`
`A` là số nguyên
`\to 2n +2 \vdots 2n-4`
` => 2n - 4 + 6 \vdots 2n -4`
Ta có ` 2n -4 \vdots 2n-4`
` => 6 \vdots 2n -4`
` => 2n -4 \in Ư(6) = { -6 ; -3 ; -2 ; -1 ; 1 ; 2 ; 3 ; 6 }`
Ta có bảng sau
\begin{array}{|c|c|}\hline 2n-4&-6&-3&-2&-1&1&2&3&6\\\hline 2n &-2&1&2&3&5&6&7&10\\\hline\end{array}
Vì `n \in Z` nên `2n` là số chẵn
\begin{array}{|c|c|}\hline 2n &-2&2&6&10 \\ \hline n&-1&1&3&5\\\hline\end{array}
Vậy ` n \in { -1 ; 1 ; 3 ; 5}`
Bài 11 : viết lại câu sau các thể khẳng định phủ định và nghi vấn Bài 12Viết lại câu sau có thể khẳng định phủ định và nghi vấn
những điều kiện nào làm cho nông nghiệp hoa kì và ca na đa phát triển đến trình độ cao
Giúp mình với ạ Lịch sử 9 bài 21 mục 2 la mã trang 82
Bài 11 ạ :)))))))))))))))))))))))))))))))))
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7. Can you me the book, please? A. move B. pass C. have D. turn 8. Nga is the phone, chatting friends. A. on – to B. on – on C. to – with D. to – to 9. My best friend is kind and . He often makes me laugh. A. funny B. nice C. shy D. boring 10. The film is very and we can’t see all of it. A. wonderful B. easy C. exciting D. boring 11. The summer camp is for students between 10 and 15. A. age B. aged C. aging D. ages 12. Mary has hair and big eyes. A. blonde, small B. a black, blue C. blonde, blue D. black, long 13. Next summer I am working as a teacher in a village near Hoa Binh city. A. volunteer B. nice C. good D. favourite 14. She is always at school and helps other students with their homework. A. hard B. hardly C. hard-working D. work hard 15. Our class is going to a pinic at the zoo on Saturday. Would you like to come with us? A. have B. take C. pass D. go 16. It’s to go home. It’s so late. A. now B. sure C. time D. like 17. Please turn the lights. The room is so dark. A. in B. on C. off D. at 18. At break time, I go to the library and books. A. go B. read C. play D. listen 19. Listen! Someone at the door. A. knock B. knocks C. is knocking D. are knocking 20. Nam football now. He’s tired. A. doesn’t play B. plays C. is playing D. isn’t playing 21. We are excited the first day of school. A. at B. with C. about D. in 22. My parents often help me my homework. A. at B. with C. about D. in 23. I am having a math lesson but I forgot my . I have some difficulty. A. calculator B. bike C. pencil case D. pencil sharpener 24. In the afternoon, students many interesting clubs. A. join B. do C. play D. read 25. School at 4.30 p.m every day. A. finish B. finishes C. go D. have IV. Complete the sentences with the Present simple or the Present continuous form of the verbs. 1. They often (visit) their parents in the holidays. 2. We (speak) French at the moment. 3. I (watch) TV about 3 hours a day. 4. My family usually (go) to the movies on Sunday. 5. Look at the girl! She (ride) a horse. 6. We (play) tennis now. 7. Minh sometimes (practice) the guitar in his room. 8. you (like) chocolate ice cream? 9. I really (like) cooking. 10. Hung can’t answer the phone because he (take) _a shower. V. Fill in each blank with a suitable verb. 1. She an oval face. 2. - Mai’s hair long or short? - It short. 3. He tall and thin. 4. Toan an athlete. He very strong. 5. Ngan short black hair. 6. What color those bikes? 7. What color Nam’s eyes? 8. What those? IV. Complete the passage with a suitable preposition. We have English lessons (1) Room 12. There are 24 tables for students and one desk for the teacher. (2) the walls, there are a lots of posters of England. There’s a cupboard at the front of the room and (3) the cupboard, there is a TV and DVD player. Sometimes we watch films. There are some bookshelves (4) the classroom. (5) the shelves, there are a lot of English books. Our books are (6) the teacher’s desk. He wants to look at our homework. Our school bags are (7) the floor, and there is some food (8) the school bags. It’s now 5.30 pm. We are (9) home, but our teacher is (10) _ school. He often stays late to prepare for tomorrow’s lessons. VII. Reorder the words and write the meaning sentences. 1. city / beautiful / a / Ho Chi Minh / is. .............................................................................................................. 2. green fields / there / are. .............................................................................................................. 3. dog / it’s / friendly / a. .............................................................................................................. 4. student / Minh / new / a / is. .............................................................................................................. 5. television / big / a / there’s. .............................................................................................................. 6. new / four / there / cars / are. .............................................................................................................. 7. are / two / pizza / there / big. .............................................................................................................. 8. ten / are / desks / small / there. ..............................................................................................................
-(x-3)/2- 2. =5(x+2)/4 Giúp mik vs ạ mik sẽ vote5🌟mình cảm ơn
Exercise 2: Choose the correct answer 1. Do you know Janelyn? Yes, of course, I (met/ meet/ is meeting) her every day! 2. I ( am / was / were ) very happy on my last vacation. 3. Where is Tom?Ah he ( is playing/ plays/played) football with his friends in the garden 5. He ( doesn’t / won’t / didn’t ) come here last night. 6. (When / where / What time ) did you see her ? – Yesterday morning. 7. We ( are visiting / will visit / visit / visited) Ha Long Bay last summer vacation. 8. Lan sometimes (goes / go / went / is going ) to the zoo. 9. When they (was / will be / were / are ) children, they often played with each other. 10. Yesterday, I ( am buying / going to buy / buy / bought ) many gifts for him on the trip to Ha Noi. 11. The animal programme (showed/ is showing/shows) on VTV3 now 12. Last autumn, I and my friends (went/go/is going) to Nha Trang beach. It was wonderful trip 13. Hurry up, we (missed/misses/are missing) the bus! 14. My uncle (played/plays/is playing) baseball 10 years ago 15. Last year, she (is teaching/teaches/taught) us Math. 16. At the moment, my sister (reads/is reading/read) a comic book. 17. Sometimes, I (am playing/play/played)__________badminton. 18. He usually (goes/is going/went) scuba diving with his friends 19. Jogging (makes/make/is making) us stronger 20. Look! They (run/are running/ran) together.
1. You .... on Tuesday. You ..... on Wednesday A. Dont arrive / arrived B. Didnt arrive / arrives C. Didnt arriving / arrived D. Didnt arrive / arrived 2. He asked me ..... I was a student A. If B. Who 3. He .... me whether I came from A. Told B. Asked C. Said D. Required 4. We couldnt buy anything because .... of the shops were open A. None B. All C. No one D. Nothing 5. He is lazy. He never does ..... work A. Some B. No C. Any D. Not *Giải thích*
Bài 10 ạ :))))))))))))))))))))))))
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